The University of North Texas library runs a fascinating exhibit and a history tour of movable and pop-up books. "The first movable books actually predate the print culture. The earliest known examples of such interactive mechanisms are by Ramón Llull (c.1235-1316) of Majorca, a Catalán mystic and poet. His works contain volvelles or revolving discs, which he used to illustrate his complex philosophical search for truth."-- via Boing Boing